Semiconductor memory device including a control circuit and at least two memory cell arrays

ABSTRACT

A memory device includes first and second memory cell arrays, and a control circuit configured to output first information indicating whether the first memory cell array is in a ready state in which the control circuit is ready to receive a command to access the first memory cell array or a busy state in which the control circuit is not ready to receive the command to access the first memory cell array, and second information indicating whether the second memory cell array is in a ready state in which the control circuit is ready to receive a command to access the second memory cell array or a busy state in which the control circuit is not ready to receive the command to access the second memory cell array.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2014-051876, filed Mar. 14, 2014, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a semiconductor memorydevice.

BACKGROUND

A semiconductor memory device may have a plurality of planes eachincluding a set of a memory cell array, a decoder, a read circuit, andthe like. If the plurality of planes is properly controlled, it ispossible for the memory device to be efficiently used.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates functional blocks of a memory device according to afirst embodiment;

FIG. 2 illustrates a system including the memory device according to thefirst embodiment;

FIG. 3 is a circuit diagram of a part of a memory cell array accordingto the first embodiment;

FIG. 4 illustrates functional blocks of a part of the memory deviceaccording to the first embodiment;

FIG. 5 illustrates an example of an operation of the memory deviceaccording to the first embodiment;

FIG. 6 illustrates a second example of the operation of the memorydevice according to the first embodiment;

FIG. 7 illustrates a third example of the operation of the memory deviceaccording to the first embodiment;

FIG. 8 illustrates another example of a memory system of the firstembodiment;

FIG. 9 illustrates an example of an operation of the memory systemaccording to the first embodiment;

FIG. 10 illustrates a reference example of the operation of the memorysystem;

FIG. 11 illustrates a fourth example of the operation of the memorydevice according to the first embodiment;

FIG. 12 illustrates functional blocks of a part of a memory deviceaccording to a second embodiment;

FIG. 13 illustrates an example of an operation of the memory deviceaccording to the second embodiment;

FIG. 14 illustrates another example of functional blocks of a part ofthe memory device according to the second embodiment;

FIG. 15 illustrates another example of the operation of the memorydevice according to the second embodiment;

FIG. 16 illustrates flow of a signal for status read according to athird embodiment;

FIG. 17 illustrates an allocation example of a bit of status dataaccording to the third embodiment;

FIG. 18 illustrates a second allocation example of the bit of the statusdata according to the third embodiment; and

FIG. 19 illustrates a third allocation example of the bit of the statusdata according to the third embodiment.

DETAILED DESCRIPTION

The present embodiment now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. In the drawings, the thickness of layers and regions may beexaggerated for clarity. Like numbers refer to like elements throughout.As used herein the term “and/or” includes any and all combinations ofone or more of the associated listed items and may be abbreviated as“/”.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “having,” “includes,” “including” and/or variationsthereof, when used in this specification, specify the presence of statedfeatures, regions, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,regions, steps, operations, elements, components, and/or groups thereof.

It will be understood that when an element such as a layer or region isreferred to as being “on” or extending “onto” another element (and/orvariations thereof), it may be directly on or extend directly onto theother element or intervening elements may also be present. In contrast,when an element is referred to as being “directly on” or extending“directly onto” another element (and/or variations thereof), there areno intervening elements present. It will also be understood that when anelement is referred to as being “connected” or “coupled” to anotherelement (and/or variations thereof), it may be directly connected orcoupled to the other element or intervening elements may be present. Incontrast, when an element is referred to as being “directly connected”or “directly coupled” to another element (and/or variations thereof),there are no intervening elements present.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, materials, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, material, region, layer or section fromanother element, material, region, layer or section. Thus, a firstelement, material, region, layer or section discussed below could betermed a second element, material, region, layer or section withoutdeparting from the teachings of the present invention.

Relative terms, such as “lower”, “back”, and “upper” may be used hereinto describe one element's relationship to another element as illustratedin the Figures. It will be understood that relative terms are intendedto encompass different orientations of the device in addition to theorientation depicted in the Figures. For example, if the structure inthe Figure is turned over, elements described as being on the “backside”of substrate would then be oriented on “upper” surface of the substrate.The exemplary term “upper”, may therefore, encompass both an orientationof “lower” and “upper,” depending on the particular orientation of thefigure. Similarly, if the structure in one of the figures is turnedover, elements described as “below” or “beneath” other elements wouldthen be oriented “above” the other elements. The exemplary terms “below”or “beneath” may, therefore, encompass both an orientation of above andbelow.

Embodiments are described herein with reference to cross sections andperspective illustrations that are schematic illustrations ofembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, a region illustrated or described as flatmay, typically, have rough and/or nonlinear features. Moreover, sharpangles that are illustrated, typically, may be rounded. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to illustrate the precise shape of a region andare not intended to limit the scope of the present invention.

The embodiment provides a semiconductor memory device which may beefficiently controlled.

In general, according to one embodiment, a memory device includes firstand second memory cell arrays, and a control circuit configured tooutput first information indicating whether the first memory cell arrayis in a ready state in which the control circuit is ready to receive acommand to access the first memory cell array or a busy state in whichthe control circuit is not ready to receive the command to access thefirst memory cell array, and second information indicating whether thesecond memory cell array is in a ready state in which the controlcircuit is ready to receive a command to access the second memory cellarray or a busy state in which the control circuit is not ready toreceive the command to access the second memory cell array.

A memory device including a plurality of planes further includes aperipheral circuit common to the plurality of planes. The memory deviceincluding the plurality of planes and the peripheral circuit is formedas a single chip, for example. A memory controller which controls thememory device designates a single-plane read which is a read from oneplane and multi-reads from the plurality of planes. In this manner, thememory device may perform the single-plane read and the multi-reads.

The memory device uses a ready/busy signal to show the memory controllerwhether the memory device is either in a ready state or in a busy state.The ready state represents a state where the controller may have accessto the memory device. The busy state represents a state where the memorydevice internally performs a certain process and consequently thecontroller does not have access to the memory device. However, even whenthe memory device is in the busy state, processes during the busy statemay include a process in which a first plane is involved, but a secondplane is not involved. Even in such a case, the memory device outputs abusy signal. Accordingly, the memory device does not receive a commandin which the second plane is involved while the memory device outputsthe busy signal. This means that the plurality of planes are noteffectively utilized.

Hereinafter, embodiments will be described with reference to thedrawings. In the following description, the same reference numerals aregiven to configuring elements having substantially the same function andconfiguration, and thus repeated description thereof will be made onlywhen necessary.

Each functional block may be executed by either hardware or computersoftware, or alternatively by combining both of these. Therefore, thefunctional block will be described below in viewpoint of the functionthereof. It is not essential to divide each functional block as in thefollowing example. A partial function may be executed by a functionalblock different from the illustrated example, or a certain functionalblock may be divided into sub-functional blocks.

In the description, when the reference numerals include a set of a firstelement consisting of numbers or alphabets and a second elementconsisting of continuing alphabets or continuing numbers without or withsubsequent hyphens or subsequent under bars, the second element enablesthe first element of the same type to be distinguished. When it is notnecessary to distinguish the first element, reference numerals omittingthe second element will be used. The description represents all thereference numerals only for the first element.

First Embodiment

FIG. 1 illustrates functional blocks of a semiconductor memory deviceaccording to a first embodiment. As illustrated in FIG. 2, asemiconductor memory device 1 is controlled by a memory controller 2.The memory controller 2 is further controlled by a host device 3, forexample, a personal computer (PC). FIG. 2 illustrates a system accordingto the first embodiment. A memory system 5 includes the memory device 1,the memory controller 2, and the host device 3. For example, the memorycontroller 2 includes elements such as a processor 21 of a centralprocessing unit (CPU), a read only memory (ROM) 22, a random accessmemory (RAM) 23, and interfaces 24, 25, 27. The memory controller 2performs various operations in such a manner that the processor 21executes a program held by the ROM 22, for example. That is, a filesystem function of the memory controller 2 is executed by the programexecuted by the processor 21. The file system performs management on thememory device and the data stored in the memory device 1. In addition,the program executed by the processor 21 executes a driver of theinterfaces 24, 25, 27. The driver controls the interfaces 24, 25, and27. The memory interface 24 controls communication of the memorycontroller 2 (processor 21) with the memory device 1. The host interface25 controls communication of the memory controller 2 (processor 21) withthe host device 3. The RAM interface 27 controls communication of theprocessor 21 with the RAM 23. The RAM 23 holds temporary data.

Similarly, the host device 3 also includes elements such as a processor31 of the CPU, a ROM 32, a RAM 33, and an interface 34, for example. Thehost device 3 performs various operations in such a manner that theprocessor 31 executes a program held by the ROM 32, for example. Theinterface 34 controls communication with the memory controller 2.

Referring back to FIG. 1, the memory device 1 includes elements such asa plurality of planes (two planes PB0 and PB1 are illustrated as anexample), a control circuit CN, an input-output circuit IOC, anaddress-command register ACL, a voltage generating circuit VG, and acore driver CDR. Each plane PB includes a cell array CA, a row decoderRD, a data circuit-page buffer DB, and a column decoder CD.

The cell array CA includes a plurality of blocks BLK. Each block BLKincludes a plurality of string groups SS. Each string group SS includesa plurality of strings STR. Each string STR includes a plurality ofmemory cells MC (not illustrated). In addition to this, elements such asa word line WL, a bit line BL, and a source line SL are disposed in thecell array CA.

The input-output circuit IOC controls an input of a command, an address,data, and control signal from the memory controller 2 or an output tothe memory controller 2. The command, the address, and the data aretransmitted onto an I/O line between the input-output circuit IOC andthe memory controller 2. For example, the control signal includescommand latch enable (CLE), address latch enable (ALE), write enable(WE), and read enable (RE).

The row decoder RD receives a block address signal from theaddress-command register ACL, and in addition, receives a word linevoltage or a selection gate voltage from the core driver CDR. Based onthe received block address signal, a string address signal, a word linecontrol signal, and a selection gate line control signal, the rowdecoder RD selects a block, a string group, a word line and the like.

The data circuit-page buffer DB temporarily holds the data read from thememory cell array CA, receives write data from outside of the memorydevice 1, and writes the received data on the selected memory cell MC.The data circuit-page buffer DB includes a sense amplifier SA. The senseamplifier SA includes a plurality of sense amplifier units respectivelyconnected to the plurality of bit lines BL. The sense amplifier SA readsthe data of the memory cell MC via the bit line BL, and detects a stateof the memory cell MC via the bit line BL. The memory device 1 may holdthe data of two or more bits in one memory cell MC.

The data circuit-page buffer DB includes a plurality of (for example,three) data caches DCA, DCB, and DCC. The column decoder CD receives acolumn address signal from the address-command register ACL, and decodesthe received column address signal. Based on the decoded address signal,the column decoder CD controls an input and an output of the data of thedata circuit-page buffer DB.

The control circuit CN receives various commands from theaddress-command register ACL. The control circuit CN controls thevoltage generating circuit VG and the core driver CDR in accordance witha predetermined sequence, based on the command. The voltage generatingcircuit VG generates various voltages (potentials) in accordance with aninstruction of the control circuit CN. The core driver CDR controls therow decoder RD and the data circuit-page buffer DB in order to controlthe word line WL and the bit line BL in accordance with the instructionof the control circuit CN.

The control circuit CN outputs a signal indicating a state of the memorydevice 1 to the memory controller 2 via the input-output circuit IOC.The signal indicating this state includes cache busy signals CBUSY0 andCBUSY1. High level signals BUSY, CBUSY0, and CBUS1 indicate a readystate, and low level signals BUSY, CBUSY0, and CBUSY1 indicate a busystate. The signals CBUSY0 and CBUSY1 will be described later.

The cell array CA has the elements and connections which are illustratedin FIG. 3. FIG. 3 is a circuit diagram of a part (two blocks BLK) of thecell array according to the first embodiment. As described above, thecell array CA includes the plurality of blocks BLK. Each block BLKincludes the plurality of string groups SS. Each string group SSincludes the plurality of strings STR. In addition, the cell array CAincludes the plurality of bit lines BL and a cell source line SL. Ineach block BLK, i+1 numbers of strings STR are connected to one bit lineBL. The variable i is 0 or a natural number.

One string STR has n+1 numbers of memory cell transistors MTr0 to MTrnwhich are connected in series, a source side selection gate transistorSSTr, and a drain side selection gate transistor SDTr. The variable n is0 or the natural number, for example 15. In each string STR, a drain ofthe transistor SSTr is connected to a source of the cell transistorMTr0. A source of the transistor SDTr is connected to a drain of thecell transistor MTr15. A source of the transistor SSTr is connected tothe source line SL. A drain of the transistor SDTr is connected to onecorresponding bit line BL.

The plurality of strings STR juxtaposed along an extending direction ofthe word line WL makes up the string group SS. For example, all thestrings STR which are juxtaposed in the extending direction of the wordline WL and are respectively connected to all the bit lines BL make upone string group SS. In each string group SS, respective gates of therespective cell transistors MTrX (the sign X is 0 or the natural number)of the plurality of strings STR are connected to the word line WLX incommon.

In each string group SS, respective gates of the respective transistorsSDTr of the plurality of strings STR are connected to a drain sideselection gate line SGDL in common. Selection gate lines SGDL0 to SGDLiare respectively disposed for the string group SS0 to the string groupSSi.

In each string group SS, respective gates of the respective transistorsSSTr of the plurality of strings STR are connected to a source sideselection gate line SGSL in common. The source side selection gate linesSGSL0 to SGSLi are respectively disposed for the string group SS0 to thestring group SSi.

A structure of the memory cell array CA is disclosed in U.S. patentapplication Ser. No. 12/407,403 filed on Mar. 19, 2009, entitled“Three-dimensional stacked non-volatile semiconductor memory”. Inaddition, the structure is disclosed in U.S. patent application Ser. No.12/406,524 filed on Mar. 18, 2009, entitled “Three-dimensional stackednon-volatile semiconductor memory”, in U.S. patent application Ser. No.12/679,991 filed on Mar. 25, 2010, entitled “Non-volatile semiconductorstorage device and method of manufacturing the same”, and in U.S. patentapplication Ser. No. 12/532,030 filed on Mar. 23, 2009, entitled“Semiconductor memory and method for manufacturing same”. These patentapplications are hereby incorporated by reference in its entirety.

The cell transistors MTr connected to one word line WL of the same oneof the strings STR out of one string group SS make up a physical unit. Astorage space of one physical unit equals one or more pages. Data isread on a page-by-page basis. Write may be executed on each page, or maybe executed on each physical unit.

In each block BLK, the word lines WLX having the same number (address)in different strings STR are connected to each other.

In order to have access to the cell transistor MTr, one block BLK isselected, and one string group SS is selected. In order to select theblock BLK, a signal for selecting the block BLK is supplied only to theblock BLK specified by a block address signal. In the selected blockBLK, this memory block selection signal causes the word line WL, and theselection gate lines SGSL and SGDL to be connected to a driver in thecore driver CDR.

Furthermore, in order to select one string group SS, the selection gatetransistors SSTr and SDTr of the selected string group SS receive avoltage for selection. In the non-selected string group SS, theselection gate transistors SSTr and SDTr receives a voltage fornon-selection. The voltage for selection is dependent on the readoperation and the write operation. Similarly, the voltage fornon-selection is dependent on the read operation and the writeoperation.

FIG. 4 illustrates functional blocks of a part of the memory deviceaccording to the first embodiment, and is an extract of severalfunctional blocks illustrated in FIG. 1. In addition, FIG. 4 alsoillustrates layout of the functional blocks. A peripheral circuit 220 isan aggregate of the elements shared by the planes PB0 and PB1illustrated in FIG. 1, and includes at least the input-output circuitIOC and the core driver CDR. The input-output circuit IOC includes ashift register 221, an input-output pad 224, and cache busy pads 228 and229. The input-output pad 224 is connected to the I/O line. The shiftregister 221 includes a plurality of register elements (data holdingelements) 222. Each of the register elements 222 holds a portion havinga predetermined size of the data transmitted from a data cache DCC. Theshift register 221 causes the data portion transmitted from the datacache DCC to be shifted from the respective register elements 222 to theregister element 222 in the downstream close to the input-output pad224. The core driver CDR includes a conversion determination circuit231. The determination circuit 231 will be described later.

A corner region 21 is provided independently for the planes PB0 and PB1,and includes an address register 211. The cache busy pads 228, 229respectively output the cache busy signals CBUSY0 and CBUSY1.

Next, referring to FIGS. 5 to 11, an operation of the memory deviceaccording to the first embodiment will be described. FIG. 5 illustratesan example of the operation of the memory device according to the firstembodiment, and illustrates a signal flowing between the memory device 1and the memory controller 2. FIG. 5 illustrates an example of aso-called single-plane read. In order to read the data in the memorydevice 1, the memory device 1 receives the signal illustrated in FIG. 5from the memory controller 2, and outputs the signal illustrated in FIG.5 to the memory controller 2.

When the read is executed, the input-output circuit IOC receives acommand C0, addresses A1 to A5, and a command C1, on the I/O line overthe times t0 to t1. At the same time, the input-output circuit IOCreceives WE which is shifted between a high level and a low level atspecific timing. WE represents the timing for acquiring the signal onthe I/O line. The input-output circuit IOC uses an edge of WE torecognize a break of the signal on the I/O line, and acquires thecommand C0, the addresses A1 to A5, and the command C1.

The input-output circuit IOC further receives CLE of a high level andALE of a high level. CLE and ALE of the high level indicate that thesignals flowing on the I/O line at the same time are respectively thecommand and the address.

The command C0 indicates that the address of a read target is followed.The command C1 instructs execution of the read. The addresses A1 and A2are column addresses which are column portions within the address of theread target. The addresses A3 to A5 are row portions within the addressof the read target, and for example, are row addresses for specifyingthe plane, the block, the string, and the page of the read target. Inthe following description and in FIG. 5, the addresses A3 to A5designate the plane PB0. That is, a set of the command C0, the addressesA1 to A5, and the command C1 designates the single-plane read. In thefollowing description, a set of inputs of the read command and theaddress during the times t0 to t1 is referred to as a read command inputRCI.

In response to the receipt of a read execution command, the core driverCDR reads the data from the address of the read target through the rowdecoder RD0 for the plane PB0, the data circuit-page buffer DB0, and thecolumn decoder CD0. The read is executed over the times t1 to t2.

For example, the read includes reset, pump setup, address transfer, acore operation, pre-fetch, and pump recovery. The reset indicatesinitialization of operations involved in the read. The pump setupindicates generation of electric potential for the read by using thevoltage generating circuit VG. The address transfer includes thetransfer of the addresses A1 to A5 to the address register 211 in acorner region 21-0. The core operation includes at least application ofpredetermined electric potential to the word line WL, the selection gatelines SGDL and SGSL, amplification of the electric potential based onthe data read on the bit line BL by using the sense amplifier SA,identification of the data, and holding of the data caches DCA, DCB, andDCC of the data. The pre-fetch includes transfer of the data of the datacache DCC of the column address designated by the (column) addresses A1and A2 to the shift register 221. That is, the pre-fetch causes thecolumn address data designated by the column addresses A1 and A2 to beset in the shift register 221. The pump recovery includes initializationof the voltage generating circuit VG.

When the read is executed, the control circuit CN outputs the signalCBUSY0 indicating the busy state. The control circuit CN outputs therespective signals CBUSY indicating the ready state and the busy statewhile the cache DCC for the plane PB0 is accessible and inaccessible.The signal CBUSY indicates a state where the cache DCC is accessible.The memory device 1 holds the data in the data caches DCA and DCB byusing the core operation, when one read (one read command) is executed.Subsequently, the memory device 1 transfers the data in the data cachesDCA and DCB to the data cache DCC by using the pre-fetch or a dedicatedcommand. The memory device 1 transfers the data in the data cache DCC tothe shift register 221, and prepares the output data from the shiftregister 221 to the input-output pad 224. In a case of read, a statewhere the data read through the core operation is set in the data cacheDCC and the data in the data cache DCC is accessible is referred to as acache ready state. In other words, as will be described later using aspecific case, the cache ready state is a state where the memory device1 may receive a command (for example, a read command, a program command,and an erase command) instructing a process (access to the plane PB)which is in the cache ready state. For example, even during a certainprocess in the first plane PB, if the second plane PB is in the cacheready state, the memory device 1 receives the command instructing theprocess (access to the second plane) in the second plane PB.

In contrast, when the read is executed, the plane PB1 is not accessed.Accordingly, the data cache DCC of the plane PB1 is also not accessed.Therefore, when the read is executed, the control circuit CN maintainsthe signal CBUSY1 for the plane PB1 to have a value indicating the readystate.

If the core operation of the read is completed at time t1, the controlcircuit CN changes the signal CBUSY0 to the ready state. In response tothe signal CBUSY0 changed to the ready state, the memory controller 2repeatedly switches RE over to a high level and a low level atpredetermined timing (toggle RE). When detecting an edge of RE, theinput-output circuit IOC outputs the data in the register element 222which is closest to the input-output pad 224 within the shift register221 to the I/O line. The input-output circuit IOC transfers the data ineach register element 222 to the register element 222 in one-stepdownstream side, and repeats this procedure for every edge of RE. As aresult, the data D0 to D2 flows to the memory controller 2 on the I/Oline.

FIG. 6 illustrates a second example of the operation of the memorydevice according to the first embodiment, and illustrates a signalflowing between the memory device 1 and the memory controller 2. Thememory device 1 receives a read command input RC10 which designates theplane PB0 as the read target at time t10. In this manner, the coredriver CDR starts the read from time t10, and causes the signal CBUSY0for the plane PB0 of the read target to be in the busy state. Details ofthe read are as described hereinbefore with reference to FIG. 5.

At time t11, the memory device 1 receives a read command input RCI1which designates the plane PB1 as the read target. At this time point,the memory device 1 is in the midst of executing the read for a readcommand input RCI0. The memory device 1 receives the read command inputRCI1, if the cache busy signal CBUSY1 regarding the plane PB1 designatedby the subsequent read command input RCI1 indicates the ready state. Thememory device 1 separately performs a process of the subsequent readcommand input RCI1, based on the combination of several conditions. Theprocess performed in response to the subsequent read command input RCI1is as follows.

First, without resetting the data caches DCA, DCB, DCC of the plane(plane PB1) designated by the subsequent read command input RCI1, thecore driver CDR maintains the data thereinside. In addition, the coredriver CDR interprets the command in the subsequent read command inputRCI1, and proceeds to perform the process based on the interpretation.The conversion determination circuit 231 determines whether thecompletion of the read command input RCI1 (completion of receipt of thecommand C1) is done before the start of the core operation regarding thepreceding read command input RCI0, that is, before the address transfer,and whether the page of the read target designated by the subsequentread command input RCI1 is the same as the page of the read targetdesignated by the preceding read command input RCI0. If a certainphysical unit provides a storage space for a plurality of pages, onlyone word line WL is associated with the physical unit. However,consequently, a plurality of page addresses is allocated thereto. Inthis case, in order to determine that two read target pages arecoincident with each other, it is not enough to cause the word lines WLto be coincident with each other. Accordingly, coincidence of positionsof the page is also required. More specifically, for example, if onephysical unit provides two storage spaces for an upper page and a lowerpage, two read targets are necessarily the upper pages or the lowerpages. The strings are not necessarily the same as each other. That is,the multi-plane read has a limitation on the coincidence of the readtarget addresses or pages. When two read command inputs RCI0 and RCI1instruct the access satisfying the limitation, and when timingrequirements are satisfied, the two read command inputs RCI0 and RCI1are converted into the multi-plane read.

If the reception of the subsequent read command input RCI1 is performedbefore the transfer of the address for a read command input RCI0 and tworead target pages are coincident with each other, the conversiondetermination circuit 231 determines that the process of the readcommand inputs RCI0 and RCI1 is performed by means of the multi-planeread. In the multi-plane read, the planes PB0 and PB1 are controlled insynchronization with each other. For the synchronization starting fromthe address transfer, the core driver CDR suspends the process in theplane PB1, and waits for the start of the address transfer in the planePB0. If the pump setup is completed, the core driver CDR transfer therespective read target addresses of the planes PB0 and PB1 to theaddress register in the corner regions 21-0 and 21-1, respectively atthe same time. Next, the core driver CDR performs the core operations inthe planes PB0 and PB1 at the same time, and reads the data to the datacaches DCC0 and DCC1 of the respective planes PB0 and PB1. Thereafter,the core driver CDR completes the read by performing the recovery of thepump. At the same time, the control circuit CN causes the signals CBUSY0and CBUSY1 to be respectively in the busy state.

In general, the multi-plane read does not include the pre-fetch. The useof the shift register 221 is shared by the planes PB0 and PB1. Thereason is because the plane is not determined without any designation onwhich plane data is to be transferred to the shift register. Therefore,after the multi-plane read, the memory controller 2 designates the planeon which the data transfer is to be performed from the data cache DCC tothe shift register 221. That is, the command C2 and CLE of the highlevel are transmitted from time t13, then the addresses A1 to A5 and ALEof the high level are transmitted, and WE is toggled. The row addressesA3 to A5 designate the row addresses including the plane (for example,the plane PB0) and the page address which are subject to the registerread. Furthermore, the memory device 1 receives the command C3instructing the execution of the register read and CLE of the high levelfrom the memory controller 2. In this manner, the core driver CDR readsthe data in the data cache DCC0 of the column address designated by theaddresses A1 and A2 of the plane PB0 designated by the addresses A3 toA5, to the shift register 221.

After the register read is instructed, the memory controller 2 togglesRE. Accordingly, the input-output circuit IOC transmits the data D0 toD2 in the shift register 221 to the memory controller 2 on the I/O line.

As described above, in order to execute the receipt of the subsequentread command input RCI1 as the multi-plane read of the read commandinputs RCI0 and RCI1, it is necessary that the receipt of the subsequentread command input RCI1 is executed before the address transferregarding the read command input RCI0, and it is necessary that two readtarget pages are coincident with each other. FIG. 7 illustrates anoperation when the condition thereof is not satisfied. FIG. 7illustrates a third example of the operation of the memory deviceaccording to the first embodiment, and illustrates a signal flowingbetween the memory device 1 and the memory controller 2.

The memory device 1 receives the read command input RCI0 at time t20. Inresponse to this, the core driver CDR starts the read regarding theplane PB0, and causes the signal CBUSY0 to be in the busy state.

The memory device 1 receives the read command input RCI1 at time t21.The time t21 is generated after the address transfer is started withregard to the plane PB0 using the preceding read command input RCI0.Therefore, the conversion determination circuit 231 determines that theprocesses of two read commands are not converted. Accordingly, the coredriver CDR continues the process regarding the plane PB0, suspends theprocess regarding the plane PB1, and waits for the completion of theprocess regarding the plane PB0. The memory device 1 causes the signalCBUSY1 to be in the busy state from time t21.

The core driver CDR recognizes that the read command input RCI0 isexecuted as the single-plane read as instructed. Based on this, the coredriver CDR performs the pre-fetch during the read regarding the planePB0.

If the process regarding the plane PB0 is completed at time t22, thecore driver CDR causes the signal CBUSY to return to the ready state,and starts the read regarding the plane PB1. However, the core driverCDR has already performed the reset and the pump setup during the readregarding the plane PB0. Therefore, the core driver CDR does not performthe reset and the pump setup again during the read regarding the planePB1. Accordingly, the core driver CDR performs the address transfer andthe core operation with regard to the plane PB1 from time t22, and thenperforms the pump recovery. The pre-fetch regarding the plane PB1 is notperformed. For example, the reason is because the data in the shiftregister 221 with regard to the plane PB0 already stored may be damaged,when the data obtained as a result of the read of the preceding planePB0 is continuously and frequently transferred to the shift register 221for serial read, if the pre-fetch of the data read from the plane PB1 isperformed on the grounds that the read regarding the plane PB1 iscompleted. As described above, when the data is transferred from thedifferent plane PB (PB0) to the shift register 221 in the background, atthe same time with the read of a certain plane PB (PB1), the pre-fetchis not performed with regard to the subsequent plane PB1. Alternatively,the above-described command C2 is separately used, thereby executing theregister read from the data cache DCC1 to the shift register 221. If thecore driver CDR completes the read regarding the plane PB1 at time t23,the control circuit CN causes the signal CBUSY1 to return to the readystate.

The memory controller 2 detects that any one of the signals CBUSY0 andCBUSY1 is in the ready state, and executes the register read from timet24. The memory controller 2 subsequently instructs the read from twoplanes, and recognizes a possibility that the process is not executed asthe multi-plane read. Therefore, it is necessary to transfer the data tothe shift register 221 as the preparation of the data output from thememory device 1. For this reason, the memory controller 2 executes theregister read by designating the row address including the plane PB andthe pages, similar to the multi-plane read, from time t24. That is, thememory controller 2 transmits the command C2 and CLE of the high levelfrom time t24, then transmits the addresses A1 to A5 and ALE of the highlevel, and toggles WE. The row addresses A3 to A5 designate the rowaddresses including the plane (for example, the plane PB0) and the pageaddress which are subject to the register read. After instructing theregister read by designating the plane PB (and the page), the memorycontroller 2 toggles RE. In this manner, the input-output circuit IOCtransmits the data D0 to D2 in the shift register 221 to the memorycontroller 2 on the I/O line.

In the second example, even when the timing requirement is satisfied,but two addresses are not coincident with each other, similar to thethird example, the read regarding the plane PB1 is completed after awaiting state, and the address transfer regarding the plane PB1 isstarted after the read of the plane PB0 is completed.

Next, referring to FIGS. 8 and 9, an operation of a memory system of thememory device according to the first embodiment will be described. FIG.8 illustrates another example of the memory system according to thefirst embodiment, and illustrates an example where the first embodimenthas a memory system 5 including a solid state device (SSD) 11 and thehost device 3. The SSD 11 includes the memory controller 2 and aplurality of memory devices 1. The processor 21, the ROM 22, and theinterfaces 24, 25, 27 are configured as hardware 12.

As illustrated in FIG. 9, a read request from the host device 3 in thememory system 5 mainly includes five stages A to E. The stage A isstarted by the read request from the host device 3, and is a stage wherea process is executed by the memory controller 2 receiving the readrequest. In the stage A, the memory controller 2, that is, the CPU 21operated in accordance with the program interprets the read request, andcalculates a position (address) where requested data is held in thememory device 1. A solution to the data holding position includes theconversion of a logical address used in communication with the hostdevice 3 by the memory controller 2 and a physical address indicatingthe actual (physical) address in the storage space of the memory device1. The memory controller 2 uses the calculated address as the readtarget address, and instructs the read to the memory device 1. The readinstruction is equivalent to the read command input RCI.

The stage B is a stage where a process instructed by the readinstruction is executed in the memory device 1. The stage B is a stagewhere the read described with reference to FIGS. 5 to 7 is executed. Thestage C is a stage of the data transfer from the memory device 1 to thememory controller 2. That is, the memory controller 2 first retrievesthe data from the memory device 1 by issuing RE, as described withreference to FIGS. 5 to 7. As illustrated by a broken line in FIG. 8,the retrieved data is subjected to error correction using an errorcorrection code (ECC) obtained by the program on the ROM 22 beingexecuted by the processor 21, and then is held on the RAM 23.

The stage D is a stage for preparation of transferring the data on theRAM 23 to the host device 3. In the stage E, as also illustrated by thebroken line in FIG. 8, the CPU 21 transfers the data on the RAM 23 tothe host device 3 via the interface 25.

It is assumed that a different read request is issued as illustrated inFIG. 9 before the completion of the read request which causes a seriesof processes described above to start. That is, it is assumed that thehost device 3 issues the read request relating to the read of the planePB0 at time t30, and issues the read request relating to the read of theplane PB1 at time t31 in the midst of the stage B regarding the planePB0.

The memory controller 2 executes the read command inputs RCI0 and RCI1to perform two read requests. Even if the process is not executed as themulti-plane read as in the example of FIG. 6, the memory device 1continuously executes the single read while omitting a part of the readas in the example of FIG. 7. By utilizing this, the memory system 5(memory controller 2) may execute the stage B (read in the memory device1) regarding the plane PB1, at the same time with the stage C (transferto the memory controller 2) regarding the plane PB0. If the execution ofthe stage E regarding the plane PB0 is completed, the memory controller2 start the execution of the stage C regarding the plane PB1.

The process as illustrated in FIG. 9 is distinguished from the referenceprocess illustrated in FIG. 10. FIG. 10 illustrates an operation of thesystem including the memory device which does not receive theinstruction regarding a different plane during the process regarding acertain plane. The memory controller receives a read request relating tothe read of the plane PB0 at time t100, executes the read command inputRCI0 regarding the plane PB0, and waits for the completion of theprocess in the memory device, thereby remaining in the stage B. Thememory controller receives the read request relating to the read of theplane PB1 at time 101. However, the memory device does not receive theread command input regarding the plane PB1. Accordingly, the memorycontroller does not execute the read command input regarding the planePB1. The memory controller may interpret the read request and maycalculate the address with regard to the plane PB1 during the stage Bregarding the plane PB0 (first half of the stage A). However, the memorycontroller may instruct the read to the memory device for the first timeafter the completion of the stage E regarding the plane PB0 (second halfof the stage A). Therefore, it takes longer time to complete the stage Eregarding the plane PB1 as compared to the example illustrated in FIG.9.

The reason why the memory device illustrated in FIG. 10 does not receivethe instruction of the read in a certain plane during the read regardinga different plane is because the data caches regarding all the planesare to be reset if the instruction of the read regarding the subsequentplane is received. In contrast, in the memory device 1, it is separatelymanaged for each plane whether or not the access to the data cache DCCis available as described above. Therefore, the receipt of theinstruction of the read regarding the data cache DCC of a certain planePB does not lead to the reset of the data cache DCC of the differentplane PB, thereby enabling the process as illustrated in FIG. 9.

FIG. 11 illustrates a fourth example of an operation of the memorydevice according to the first embodiment. FIG. 11 relates to a program.The program is also basically the same as the read. First, the memorycontroller 2 executes a program command input PCI0 with respect to thememory device 1 at time t40. The program command input PCI0 includes aprogram address transfer command C5, program addresses A1 to A5, data D0to Dn (sign n is a natural number), and a program execution command C6.The program command input PCI0 is the same as the read command inputRCI0 in that CLE, ALE, and WE become logically valid, at the same timewith the flow of the command, the address, and the data on the I/O line.

When receiving the program command input PCI0, the memory device 1executes the program. Similar to the read, the program includes thereset, the pump setup, the address transfer, the core operation, and thepump recovery. The reset, the pump setup, the address transfer, and thepump recovery are respectively similar to those in the read. The coreoperation includes at least the transfer of the program data to the datacache DCC0, and the application of predetermined electric potential tothe word line WL, the bit line BL, and selection gate lines SGDL andSGSL which are executed by the core driver CDR. The data cache DCC0 isaccessed by the program. Accordingly, the control circuit CN causes thesignal CBUSY0 to be in the busy state when receiving the program commandinput PCI0. In contrast, the signal CBUSY1 indicates the ready state.The memory controller recognizes that the signal CBUSY1 is in the readystate, and then may start the program executed for the plane PB1. Forthis reason, the memory controller 2 executes the program command inputPCI1 at time t41. The time t41 is in the midst of executing the coreoperation regarding the plane PB0. Therefore, the memory device 1 waitsfor the completion of the program regarding the plane PB0, and outputsthe signal CBUSY1 indicating the busy state.

The control circuit CN completes the program regarding the plane PB0 attime t42, and causes the signal CBUSY0 to be in the ready state. Thecore driver CDR restarts the program regarding the plane PB1 at timet42. However, similar to the read, the core driver CDR does not executethe reset and the pump setup again during the program regarding theplane PB1. Accordingly, the core driver CDR executes the addresstransfer and the core operation with regard to the plane PB1 from timet42, and then executes the pump recovery. If the program regarding theplane PB1 is completed, the control circuit CN causes the signal CBUSY1to return to the ready state.

As described above, the memory device according to the first embodimenthas the pads 228 and 229 for outputting the dedicated cache busy signalCBUSY to each plane PB, and may receive the process (that is, thecommand) regarding the different plane PB in the cache ready stateduring the process regarding a certain plane PB. Therefore, the memorydevice 1 may use the different plane PB while the memory device 1executes the process regarding a certain plane PB. For example, thememory device 1 may be used in order to temporarily hold some data. Thismay reduce the capacity of the cache executed by the RAM 23 in acontroller (for example, the memory controller 2) used together with thememory device 1. In addition, the memory device 1 may receive thereservation of the read command input. Therefore, a device forcontrolling the memory device 1 (memory controller 2 and the like) mayexecute a plurality of processes, partially in parallel, therebyenabling an efficient process in the overall memory system 5.

In addition, the memory device 1 continuously executes the processregarding the plane PB which instructed after the completion of theprocess regarding the plane PB which is previously instructed. If theread regarding the different plane PB is instructed after the readregarding a certain plane PB is instructed so as to satisfy a specificcondition, the memory device 1 executes these instructions as themulti-plane read. Therefore, it is possible to more efficiently executeparallel operations for the plurality of planes PB. Furthermore, thememory device according to the first embodiment omits a part of processregarding the subsequent plane, when the process regarding the pluralityof planes PB is continuously executed. Therefore, it is possible to morequickly complete the continuous execution of the process regarding theplurality of planes. Even in a case of the program, an advantageouseffect which is the same as that of the read may be obtained.

Second Embodiment

In a second embodiment, a pad indicating whether or not the cache isreserved is provided, and a signal indicating that the cache is reservedis communicated.

FIG. 12 illustrates functional blocks of a part of the memory deviceaccording to the second embodiment, and illustrates details of theinput-output circuit IOC and the corner region 21. The input-outputcircuit IOC includes a queue cache busy pad 241 instead of the cachebusy pad 229 in the first embodiment. The pad 241 outputs a queue cachebusy signal QCBUSY. In addition, the corner region 21 includes addressregisters 212 a and 212 b. In order to simplify the description and tofacilitate the understanding, the second embodiment relates to anexample where the memory device 1 has one plane PB. Based on this, thereis provided the cache busy signal CBUSY regarding one plane PB.

FIG. 13 illustrates an example of an operation of the memory deviceaccording to the second embodiment. At time t50, the memory controller 2executes a read command input RCI-1 in which a page L is a readingtarget, with respect to memory device 1. In response to this, thecontrol circuit CN causes the signal CBUSY to be in the busy state fromtime t50, and executes the read from time t50. During the read, theaddress regarding the read command input RCI-1 is transferred to avacant register between two address registers 212 a and 212 b. In theexample illustrated herein, the address (page L address) is transferredto the address register 212 a and the address register 212 b is vacant,as shown in FIG. 13. The control circuit CN maintains the signal QCBUSYto be in the high level at the time point of time t50.

At time t51, the memory controller 2 executes a read command input RCI-2in which a page M is a reading target, with respect to memory device 1.Then, the memory device 1 executes the read after finishing the read ofthe page L. Although the signal CBUSY is in the busy state at time t51,the signal QCBUSY is in the ready state. Therefore, the memory device 1may receive the reservation of the subsequent read command input RCI.That is, the memory device 1 transfers the address in a different readcommand input RCI which is received during the process of a certain readcommand input RCI to the address register 212 a or 212 b which is vacant(for example, the address register 212 b), and waits. In addition, thememory device 1 causes the signal QCBUSY to be in the busy state (queuebusy state) from time t51. The memory device 1 does not receive the readcommand input RCI while the signals BUSY and QCBUSY are both in the busystate. That is, while the memory device 1 has the read command input RCIwhose process is not completed and waits for the subsequent read thathas been reserved, the memory device 1 does not receive another readcommand input RCI.

At time t52, the memory device 1 completes the read regarding the readcommand input RCI-1, and the memory controller 2 is in a state ofretrieving the data (data of the page L) regarding the read commandinput RCI-1. The page M address data stored in the address register 212b is transferred to the address register 212 a. At this time, theaddress registers 212 b is vacant. Accordingly, the memory device 1causes the signal CBUSY to be in the ready state. If the signal CBUSY isin the ready state, the memory device 1 may receive the read commandinput RCI. From time t52, the core driver CDR continuously executes theread regarding the read command input RCI-1, and executes the readregarding the read command input RCI-2. At this time, as described inthe first embodiment, two reads are continuously executed. In the secondread, the reset and the pump setup are not executed. Therefore, it ispossible to quickly complete the subsequent read.

At time t53, the memory controller 2 executes a read command input RCI-3in which a page N is a reading target, with respect to the memory device1.

At this time, the signal CBUSY is in the ready state. Accordingly, thememory device 1 receives the read command input RCI-3. The address inthe read command input RCI-3 is transferred to the address register 212a or 212 b which is vacant. In the example illustrated herein, theaddress (page N address) is transferred to the address register 212 a,as shown in FIG. 13. The control circuit CN causes the signal CBUSY tobe in the busy state at time t53, based on that the read command inputRCI-3 is executed.

At time t54, the memory device 1 completes the read regarding the readcommand input RCI-2, and the memory controller 2 is in a state ofretrieving the data (data of the page M) regarding the read commandinput RCI-2. Accordingly, the memory device 1 causes the signal CBUSY tobe in the ready state. There is no more reserved read command input RCI.Therefore, at time t55 after the lapse of a certain time period fromtime t54, the memory device 1 may receive another read command inputRCI. Accordingly, the control circuit CN causes the signal QCBUSY toreturn to the ready state.

FIG. 13 illustrates that a cache data transfer command input CCI isfurther executed at time t56. When the continuous read is completedthrough the read of the page N, the data of the page M is in a state ofbeing held in the data cache DCC. The data of the page M is held in thesense amplifier SA. Therefore, the cache data transfer command input CCIis required in order to transfer the data of the page M from the datacache 133 to the data cache DCC. When receiving the cache data transfercommand input CCI, the memory device 1 causes the signal CBUSY to be inthe busy state, transfers the data of the page M from the data cache 133to the data cache DCC, and causes the signal CBUSY to return to theready state. In this manner, the memory controller 2 is in a state ofretrieving the data of the page M.

FIG. 14 illustrates a second example of the functional blocks of a partof the memory device according to the second embodiment, and illustratesdetails of the input-output circuit IOC and the corner region 21. FIG.13 also relates to an example where the memory device 1 has one plane.The input-output circuit IOC includes a cache busy pad 242 instead ofthe queue cache busy pad 241 in the example illustrated in FIG. 13. Thepad 242 outputs a cache busy signal CBUSY2. According to the exampleillustrated in FIG. 14, it is possible to achieve the operation which isthe same as that in the examples in FIGS. 12 and 13.

FIG. 15 illustrates an operation of the second example of the memorydevice according to the second embodiment. The process at time t60 isthe same as the process at time t50. At subsequent time t61, similar toa case at time t51, the memory controller 2 execute a read command inputRCI-1 in which the page M is a read target, with respect to the memorydevice 1. At the time point of time t61, the memory device 1 has alreadyexecuted the read. Although the signal CBUSY is in the busy state, thesignal CBUSY2 is in the ready state. Therefore, the memory device 1 mayreceive the reservation of the subsequent read command input RCI. Thatis, similar to the case at time t51 in FIGS. 12 and 13, the memorydevice 1 transfers the address in a different read command input RCIreceived during the process of a certain read command input RCI to theaddress register 212 a or 212 b which is vacant, and waits. In addition,the memory device 1 causes the second cache busy signal CBUSY2 to be inthe busy state. The memory device 1 does not receive the read commandinput RCI while the signals CBUSY and CBUSY2 are both in the busy state.

The process at time t62 is the same as the process at time t52. At timet63, similar to the case at time t53, the memory controller 2 executesthe read command input RCI-3 in which the page N is a read target, withrespect to the memory device 1. At this time, when any one of twosignals CBUSY and CBUSY2 is in the ready state, the memory device 1receives the read command input RCI-3, and then executes the processwhich is the same as the process at time t53. There is no more reservedread command input RCI. Therefore, at time t64 after the lapse of acertain time period from time t63, the memory device 1 may receiveanother read command input RCI. Accordingly, the control circuit CNcauses the signal CBUSY2 to return to the ready state. At time t64, thememory device 1 completes the read for the read command input RCI-2.Therefore the memory controller 2 is in a state of retrieving the data(data of the page M) regarding the read command input RCI-2 from thetime t64.

At time t65, the memory device 1 completes the read for the read commandinput RCI-3. Accordingly, the memory device 1 causes the signal CBUSY tobe in the ready state. The subsequent process at time t66 is the same asthe process at time t56.

As described above, the memory device according to the second embodimentmay receive the reservation of the read command input RCI even if thememory device has the read command input RCI whose process is notcompleted. It is possible to indicate whether or not the read commandinput RCI is reserved, by using the signal QCBUSY or CBUSY2 in additionto the cache busy signal CBUSY. The read regarding the reserved readcommand input RCI is continuously executed in the read regarding theread command which is in the processing. The memory device 1 may receivethe reservation of the read command input RCI. Therefore, a device forcontrolling the memory device 1 (memory controller 2 and the like) mayexecute a plurality of processes, partially in parallel, therebyenabling an efficient process in the overall memory system 5.

When a plurality of reads is continuously executed, a process regardingthe following read is partially omitted. Accordingly, similar to thecase where the processes regarding the plurality of planes arecontinuously executed in the first embodiment, it is possible to morequickly complete the execution for the plurality of reads.

Third Embodiment

A third embodiment relates to a modification of the first and secondembodiments, and relates to another example of the signals QCBUSY andCBUSY2 of the second embodiment and signals CBUSY0 and CBUSY1 of thefirst embodiment.

Without using the dedicated pads 228, 229, and 241 as described above,notification of the signals CBUSY0, CBUSY1, QCBUSY, and CBUSY2 may beperformed by status read. That is, as illustrated in FIG. 16, the memorydevice 1 outputs status data via the I/O line, when receiving a statusread command. The status data includes a plurality of bits, for exampleeight bits. Information of the signals CBUSY0, CBUSY1, CBUSY, QCBUSY,and CBUSY2 is allocated to any one of the plurality of bits of thestatus data. FIG. 17 illustrates an allocation example of the bits ofthe status data according to the third embodiment, and illustrates anexample of a relationship between the information indicating statesincluding a state indicated by the signals CBUSY0 and CBUSY1 accordingto the first embodiment and the bits of the status data. I/O[0] toI/O[7] correspond to the bit in the status data output by the statusread command used in the memory device 1 which may notify a state byusing the signals CBUSY0 and CBUSY1 as in the first embodiment, andrespectively correspond to eight bits in the I/O line.

For example, I/O[0] is not used. I/O[1] and I/O[2] respectively indicatetrue ready/busy of the planes PB0 and PB1, and respectively indicateready and busy by using “1” and “0”, for example. The true busyindicates that a certain operation is performed inside the memory device1. When a certain operation is performed inside the planes PB0 and PB1,I/O[1] and I/O[2] respectively indicate “0”. More details are asfollows. The ready/busy state of the semiconductor memory device has twotypes. The memory device 1 according to the embodiments also has twotypes of ready/busy state of the chip. For example, a case will bedescribed where the memory device 1 is instructed to execute the readfor multiple continuous pages. If the data read from a certain page istransferred to the data cache DCC and then the pre-fetch to the shiftregister 221 is completed, the state becomes cache ready. Therefore, thedata from the memory device 1 to the memory controller 2 may be output.During this time, those other than the data cache DCC and the shiftregister 221 are in an inactive state. Accordingly, the memory device 1may execute the core operation such as the read using the data caches(for example, data caches DCA and DCB) other than the data cache DCC.Therefore, a command to automatically start the read the subsequent pageafter the read of a certain page is executed is prepared. An operatingmethod of reducing the inactive state as much as possible by executingthe core operation (for example, the read) for a different page in thebackground whereas the memory controller 2 may output the data of acertain page in the foreground is called a cache operation. In thisexample, the operating method is the cache operation regarding the read,and thus, is also called cache read. This state is cache ready. Incontrast, this state represents a state where the core operation isexecuted by using those other than a circuit for an access to the datacache, and is called a true busy state. As illustrated in FIG. 5, in theread where the cache operation is not executed, the cache busy is equalto the true busy.

I/O[3] indicates a value (“0”) indicating busy if at least any onebetween I/O[1] and I/O[2] indicates busy, and indicates “1” if not.I/O[4] and I/O[5] respectively indicate cache ready/busy for the planesPB0 and PB1, respectively correspond to the signals CBUSY0 and CBUSY1,and respectively indicate ready and busy by using “1” and “0”, forexample. That is, in the status data in which the signals CBUSY0 andCBUSY1 are output during the busy state in the first embodiment, I/O[4]and I/O[5] respectively indicate “0”. I/O[6] indicates a value (“0”)indicating busy if at least any one between I/O[4] and I/O[5] indicatesbusy, and indicates “1” if not.

I/O[7] indicates able and disable of write protect. For example, if thewrite is protected, I/O[7] indicates “0”. If the write is not protected,I/O[7] indicates “1”.

If the status read command is input to the memory device 1 which outputsthe status data illustrated in FIG. 17, the memory device 1 outputs thestatus data of FIG. 17 in which each bit has a value determined based onthe state thereof. For example, if the status read data indicates thatthe plane PB0 indicates cache busy and the plane PB1 indicates cacheready, that is, if I/O[4] and I/O[5] respective indicate “0” and “1”,the access to the data cache DCC1 of the plane PB1 is possible.

FIG. 18 illustrates a second allocation example of the bits of thestatus data according to the third embodiment, and illustrates anexample of a relationship between the information indicating statesincluding a state indicated by the signals CBUSY and QCBUSY according tothe second embodiment and the bits of the status data. I/O[0] to I/O[7]correspond to the bit in the status data output by the status readcommand used in the memory device 1 which may notify a state by usingthe signals CBUSY and QCBUSY as in the second embodiment, andrespectively correspond to eight bits in the I/O line.

For example, I/O[0] indicates chip N status, and indicates whether aprogram or erase passes or fails after the program or the erase iscompleted in the memory device 1. For example, I/O[0] indicates the passand the fail, respectively by using “0” and “1”. I/O[1] indicates chipN−1 status, and indicates whether the program for the preceding pagepasses or fails when there are two continuous page program. For example,I/O[1] indicates the pass and the fail, respectively by using “0” and“1”. For example, I/O[2] and I/O[3] are not used.

I/O[4] indicates cache ready/busy, and for example, indicates ready andbusy, respectively by using “1” and “0”. I/O[4] corresponds to thesignal QCBUSY. That is, I/O[4] indicates “0” in the status data wherethe signal QCBUSY is output during the busy state in the secondembodiment. I/O[5] indicates true ready/busy, and is the same as thatillustrated in FIG. 17. I/O[6] indicates cache ready/busy, and forexample, indicates ready and busy, respectively by using “1” and “0”.I/O[6] corresponds to the signal QCBUSY. That is, I/O[6] indicates “0”in the status data where the signal QCBUSY is output during the busystate in the second embodiment. I/O[7] indicates write protect, and isthe same as that illustrated in FIG. 17.

FIG. 19 illustrates a third allocation example of the bits of the statusdata according to the third embodiment, and illustrates an example of arelationship between the information indicating states including a stateindicated by the signals CBUSY and CBUSY2 according to the secondembodiment and the bits of the status data. I/O[0] to I/O[7] correspondto the bit in the status data output by the status read command used inthe memory device 1 which may notify a state by using the signals CBUSYand CBUSY2 as in the second embodiment, and respectively correspond toeight bits in the I/O line.

For example, I/O[0] and I/O[1] indicate chip N status and chip N−1status, and are the same as those illustrated in FIG. 18. For example,I/O[2] and I/O[3] are not used. I/O[4] indicates true ready/busy, and isthe same as that illustrated in FIG. 18. I/O[5] indicates second cacheready/busy, and for example, indicates ready and busy, respectively byusing “1” and “0”. I/O[5] corresponds to the signal CBUSY2. That is,I/O[5] indicates “0” in the status data where the signal CBUSY2 isoutput during the busy state in the second embodiment. I/O[6] indicatescache ready/busy, and for example, indicates ready and busy,respectively by using “1” and “0”. I/O[6] corresponds to the signalCBUSY. That is, I/O[6] indicates “0” in the status data where the signalCBUSY is output during the busy state in the second embodiment. I/O[7]indicates write protect, and is the same as that illustrated in FIG. 17.

As described above, the memory device according to the third embodimentis based on the first or second embodiment. The memory device accordingto the third embodiment is capable of notifying a state indicated by thesignals CBUSY0 and CBUSY1 of the first embodiment or the signals CBUSY,QCBUSY, and CBUSY2 of the second embodiment by using the status read andthe status data. Therefore, an advantageous effect which is the same asthat of the configuration based on the third embodiment between thefirst and second embodiments may be obtained.

In addition, the respective embodiments are not limited to thosedescribed above. The respective embodiments may be modified in variousways in an embodying stage without departing from the spirit of theinvention. Furthermore, the above-described embodiments include variousstages. Various embodiments may be extracted by appropriately combininga plurality of configuring elements disclosed herein. For example, evenwhen some configuring elements are deleted from all the configuringelements described in the above-described respective embodiments, aconfiguration from which the configuring elements are deleted may beextracted as an embodiment.

When the memory device 1 according to the present embodiments is aNAND-type flash memory, the following operation and configuration may beemployed.

(1) In a read operation (read) of multi-valued levels, if an A level, aB level, and a C level are arranged sequentially from the level havingthe lowest threshold voltage, a voltage applied to the word lineselected for the read operation of the A level is in a range of 0 V to0.55 V, for example. Without being limited thereto, the voltage may bein any range of 0.1 V to 0.24 V, 0.21 V to 0.31 V, 0.31 V to 0.4 V, 0.4V to 0.5 V, and 0.5 V to 0.55 V.

A voltage applied to the word line selected for the read operation ofthe B level is in a range of 1.5 V to 2.3 V, for example. Without beinglimited thereto, the voltage may be in any range of 1.75 V to 1.8 V, 1.8V to 1.95 V, 1.95 V to 2.1 V, and 2.1 V to 2.3 V.

A voltage applied to the word line selected for the read operation ofthe C level is in a range of 3.0 V to 4.0 V, for example. Without beinglimited thereto, the voltage may be in any range of 3.0 V to 3.2 V, 3.2V to 3.4 V, 3.4 V to 3.5 V, 3.5 V to 3.7 V, and 3.7 V to 4.0 V.

Time (tR) for the read operation may be in any range of 25 μs to 38 μs,38 μs to 70 μs, and 70 μs to 80 μs.

(2) A write operation includes a program operation and a verifyoperation. In the write operation, a voltage first applied to the wordline selected during the program operation is in a range of 13.7 V to14.3 V, for example. Without being limited thereto, for example, thevoltage may be in any range of 13.7 V to 14.0 V and 14.0 V to 14.7 V.

The voltage first applied to the selected word line during the write ofthe odd-numbered word line may be changed to the voltage first appliedto the selected word line during the write of the even-numbered wordline.

When the program operation uses an incremental step pulse program (ISPP)method, a step-up voltage may be approximately 0.5 V, for example.

A voltage applied to the non-select word line may be in a range of 7.0 Vto 7.3 V, for example. Without being limited this case, the voltage maybe in a range of 7.3 V to 8.4 V, or alternatively, may be 7.0 V or less.

An applying pass voltage may be changed depending on whether thenon-select word line is the odd-numbered word line or depending onwhether the non-select word line is the even-numbered word line.

Time (tProg) for the write operation may be in any range of 1,700 μs to1,800 μs, 1,800 μs to 1,900 μs, and 1,900 μs to 2,000 μs, for example.

(3) In an erase operation, a voltage first applied to a well which isformed in an upper portion of a semiconductor substrate and where thememory cell is arranged above is in a range of 12 V to 13.7 V, forexample. Without being limited to this case, the voltage may be in anyrange of 13.7 V to 14.8 V, 14.8 V to 19.0 V, 19.0 V to 19.8 V, and 19.8V to 21 V.

Time (tErase) for the erase operation may be in any range of 3,000 μs to4,000 μs, 4,000 μs to 5,000 μs, and 4,000 μs to 9,000 μs, for example.

(4) The memory cell has a charge storage layer arranged on thesemiconductor substrate (silicon substrate) via a tunnel insulating filmhaving the film thickness of 4 nm to 10 nm. This charge storage layermay have a layer structure of an insulating film made of SiN or SiONwhich has the film thickness of 2 nm to 3 nm and polysilicon having thefilm thickness of 3 nm to 8 nm. Metals such as Ru may be added to thepolysilicon. The insulating film is formed on the charge storage layer.For example, the insulating film has a silicon oxide film which has thefilm thickness of 4 nm to 10 nm and which is interposed between a lowerlayer High-k film having the film thickness of 3 nm to 10 nm and anupper layer High-k film having the film thickness of 3 nm to 10 nm. TheHigh-k film includes HfO. In addition, the film thickness of the siliconoxide film may be thicker than the film thickness of the High-k film. Acontrol electrode having the film thickness of 30 nm to 70 nm is formedon the insulating film via a work function adjusting material having thefilm thickness of 3 nm to 10 nm. Here, the work function adjustingmaterial is a metal oxide film made of TaO or a metal nitride film madeof TaN. As the control electrode, W may be used.

In addition, an air gap may be formed between the memory cells.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A semiconductor memory device, comprising: firstand second memory cell arrays; a control circuit configured to outputfirst information indicating whether the first memory cell array is in aready state in which the control circuit is ready to receive a commandto access the first memory cell array or a busy state in which thecontrol circuit is not ready to receive the command to access the firstmemory cell array, and second information indicating whether the secondmemory cell array is in a ready state in which the control circuit isready to receive a command to access the second memory cell array or abusy state in which the control circuit is not ready to receive thecommand to access the second memory cell array, wherein the controlcircuit includes a first pad through which the first information isoutput and a second pad through which the second information is output;and first and second caches that respectively hold data transferred fromthe first and second memory cell arrays, wherein when the firstinformation indicates that the first memory cell array is in the readystate, the first cache is accessible from outside the device, when thesecond information indicates that the second memory cell array is in theready state, the second cache is accessible from outside the device, andwhen the control circuit receives a first command to access the firstmemory cell array and a second command to access the second memory cellarray after receiving the first command, the control circuit isconfigured to perform a process instructed by the first command and thenperform a process instructed by the second command within a time periodthat is shorter than two times a time period for completing the processinstructed by the first command.
 2. The device according to claim 1,wherein if the first command and the second command accesses a same pagein the first and second memory cell arrays, the same page in the firstand second memory cell arrays are accessed at the same time.
 3. Thedevice according to claim 1, wherein, while the control circuit isexecuting the process instructed by the first command, the controlcircuit suspends the process instructed by the second command so thatthe same page in the first and second memory cell arrays can be accessedat the same time.
 4. The device according to claim 1, wherein if thefirst command and the second command accesses a different page in thefirst and second memory cell arrays, a page in the first memory cellarray is accessed and thereafter a page in the second memory cell arrayis accessed.
 5. The device according to claim 1, wherein the firstinformation and the second information are output as a series of statusbits.
 6. A semiconductor memory device, comprising: first and secondmemory cell arrays; and a control circuit configured to output firstinformation indicating whether the control circuit is in a first readystate or a first busy state and second information indicating whetherthe control circuit is in a second ready state or a second busy state,wherein the control circuit is ready to receive a first command toaccess the first memory cell array when in the first ready state and isnot ready to receive the first command when in the first busy state, thecontrol circuit is ready to receive a second command to access thesecond memory cell array when in the second ready state and not ready toreceive the second command when in the second busy state, the controlcircuit is configured to output the first information indicating thecontrol circuit is in the first busy state after the semiconductormemory device receives the first command and to perform a first coreoperation in the first memory cell array while in the first busy state,and the control circuit is configured to be able to receive the secondcommand while in the first busy state, wait until the first coreoperation is finished, and then perform a second core operation in thesecond memory cell array.
 7. The device according to claim 1, whereinthe control circuit is configured to perform the second core operationonce the control circuit outputs the first information indicating thecontrol circuit is in the first ready state after the first coreoperation is finished.
 8. The device according to claim 1, wherein thecontrol circuit is configured to output the second informationindicating the control circuit is in the second busy state afterreceiving the second command.
 9. The device according to claim 1,wherein the control circuit is configured to perform a first pre-fetchoperation and a first dummy end operation while in the first busy state.10. The device according to claim 9, wherein the control circuit isconfigured to perform a second address transfer operation afterperforming the first dummy end operation and before performing thesecond core operation.
 11. The device according to claim 6, wherein thefirst and second core operations are read operations.
 12. The deviceaccording to claim 6, wherein the first information and the secondinformation are output as a series of status bits.
 13. The deviceaccording to claim 6, wherein the control circuit includes a first padthrough which the first information is output and a second pad throughwhich the second information is output.
 14. The device according toclaim 6, wherein the control circuit is configured to perform anoperation instructed by the first command and then perform an operationinstructed by the second command within a time period that is shorterthan two times a time period for completing the operation instructed bythe first command.
 15. The device according to claim 6, wherein thecontrol circuit includes a first register for storing an addressspecified in the first command and a second register for storing anaddress specified in the second command.